There are a couple of options...

OTO T-528 (electric) 1:8 scale
Nuova Faor SF-509 (electric and nitro) 1:5 scale
Thunder Tiger makes the Ducati 999 (electric and nitro) 1:5 scale
Venom GP1V (electric) 1:8 scale
Kyosho NSR500 (electric) 1:8 scale
Kyosho Suzuki RGV (electric) 1:8 scale

1:8 scale bikes need a lil less room to run
1:8 scale are more sensitive to bumps and debris, thus 1:5 can run faster

1:5 scale and 1:8 scale have equal stability
1:5 is a lil easier to maintain since theres more room

Nitro is noisier, messier, but not necessarily faster
Electric with lipo and brushless now have run times similar to nitro

I run Kyosho 1:8 bikes with brushless motors and 2S lipos. Very inexpensive, easy to maintain, and dont need too much space.